Turn Signal and Hazard Lamps
Printable View (105 KB)
Refer to Wiring Diagrams Cell 90 for schematic and connector information.
Inspection and Verification
1. Verify the customer concern.
2. Visually inspect for obvious signs of mechanical or electrical damage.
Visual Inspection Chart
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
NOTE: Make sure the headlamp switch is in the OFF position.
4. If the cause is not visually evident, connect the diagnostic tool to the data link connector and select the vehicle to be tested from the diagnostic tool menu. If the diagnostic tool does
not communicate with the vehicle:
check that the program card is correctly installed.
check the connections to the vehicle.
check the ignition switch position.
5. If the diagnostic tool still does not communicate with the vehicle, refer to the diagnostic tool operating manual.
6. Carry out the diagnostic tool data link test. If the diagnostic tool responds with:
SCP, ISO or UBP circuits, all electronic control units no response/not equipped, refer to Section 418-00.
No response/not equipped for FEM, refer to Section 418-00.
No response/not equipped for REM, refer to Section 418-00.
No response/not equipped for instrument cluster, refer to Section 413-00.
SYSTEM PASSED, retrieve and record the continuous diagnostic trouble codes (DTCs), erase the continuous DTCs and carry out self-test diagnostics for the FEM.
7. If the DTCs retrieved are related to the concern, go to the Front Electronic Module (FEM) Diagnostic Trouble Code (DTC) Index, the Rear Electronic Module (REM) Diagnostic
Trouble Code (DTC) Index or the Instrument Cluster Diagnostic Trouble Code (DTC) Index.
8. If multiple symptoms exist, check the Switched System Power (SSP) Relay Index before proceeding to the next step. Refer to Headlamps in this section.
9. If no DTCs related to the concern are retrieved, GO to Symptom Chart to continue diagnostics.
NOTE: For a complete master list of DTCs, refer to Section 418-00.
Front Electronic Module (FEM) Diagnostic Trouble Code (DTC) Index
SECTION 417-01: Exterior Lighting 2003 Thunderbird Workshop Manual
DIAGNOSIS AND TESTING
Procedure revision date: 03/04/2003
Special Tool(s)
73III Automotive Meter
105-R0057 or equivalent
Worldwide Diagnostic System (WDS)
418-F224,
New Generation STAR (NGS) Tester
418-F052, or equivalent diagnostic tool with appropriate adapter cable
Mechanical Electrical
Multifunction switch
Battery junction box (BJB) fuse(s):
3 (10A) (LH rear lamp)
7 (10A) (RH rear lamp)
Central junction box (CJB) fuse(s):
8 (5A) (RH front parking/turn lamp)
10 (5A) (LH front parking/turn lamp)
Circuitry
Bulbs
Front electronic module (FEM)
Rear electronic module (REM)
Instrument cluster
DTC Description Source Action
B1342 ECU Is Defective FEM CLEAR the DTCs. RETRIEVE the DTCs. If DTC B1342 is retrieved, INSTALL a new FEM. REFER to Section 418-00.
B1499 Lamp Turn Signal Left Circuit Failure FEM If inoperative, GO to Pinpoint Test Q.
If always on, GO to Pinpoint Test R.
B1501 Lamp Turn Signal Left Circuit Short to Battery FEM GO to Pinpoint Test Q.
B1503 Lamp Turn Signal Right Circuit Failure FEM If inoperative, GO to Pinpoint Test Q.
If always on, GO to Pinpoint Test R.
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Rear Electronic Module (REM) Diagnostic Trouble Code (DTC) Index
Instrument Cluster Diagnostic Trouble Code (DTC) Index
Symptom Chart
Connector Circuit Reference
Front Electronic Module (FEM) C201a
B1505 Lamp Turn Signal Right Circuit Short to Battery FEM GO to Pinpoint Test Q.
DTC Description Source Action
B1342 ECU Is Defective REM CLEAR and DOCUMENT the DTCs. CARRY OUT the instrument cluster self-test. INSTALL a new REM if DTC B1342 is retrieved
again. REFER to Section 418-00.
B2529 Left Rear Turn Lamp Circuit Failure REM If inoperative, GO to Pinpoint Test N.
If always on, GO to Pinpoint Test O.
B2530 Left Rear Turn Lamp Circuit Short to
Battery
REM GO to Pinpoint Test N.
B2535 Right Rear Turn Lamp Circuit Failure REM If inoperative, GO to Pinpoint Test N.
If always on, GO to Pinpoint Test O.
B2536 Right Rear Turn Lamp Circuit Short to
Battery
REM GO to Pinpoint Test N.
DTC Description Source Action
B1342 ECU Is Defective Instrument
cluster
CLEAR and DOCUMENT the DTCs. CARRY OUT the instrument cluster Self-Test. INSTALL a new instrument cluster if
DTC B1342 is retrieved again. REFER to Section 413-00.
B1875 Turn Signal/Hazard Switch Signal
Circuit Failure
Instrument
cluster
GO to Pinpoint Test S.
Symptom Chart
Condition Possible Sources Action
No communication with the front
electronic module (FEM)
Circuitry.
FEM.
REFER to Section 418-00.
No communication with the rear
electronic module (REM)
Circuitry.
REM.
REFER to Section 418-00.
No communication with the
instrument cluster module
Circuitry.
Instrument cluster.
REFER to Section 413-00.
The turn signal lamps are
inoperative
Circuitry.
Multifunction switch.
Instrument cluster.
GO to Pinpoint Test P.
The turn signal lamps are always on
Multifunction switch.
INSTALL a new multifunction switch. REFER to Section 211-00. TEST the system for
normal operation.
One turn signal lamp is inoperative
Circuitry.
Rear electronic
module (REM).
Front electronic
module (FEM).
GO to Pinpoint Test Q.
One turn signal lamp is always on
Circuitry.
Front electronic
module (FEM).
GO to Pinpoint Test R.
The hazard lamps are inoperative
Multifunction switch.
CARRY OUT the multifunction switch component test.
If the multifunction switch is OK, INSTALL a new instrument cluster. REFER to
Section 413-00. TEST the system for normal operation.
If the multifunction switch is not OK, INSTALL a new multifunction switch.
REFER to Section 211-00. TEST the system for normal operation.
The hazard lamps are always on
Circuitry.
Multifunction switch.
Instrument cluster.
GO to Pinpoint Test S.
Pin Number
(s) Circuit Designation/Description Normal Condition/Measurement
4 31S-LG18 (BK/YE) RH front turn lamp control ground
circuit
Less than 5 ohms between the FEM and the RH front turn lamp. Greater than 10 volts with the ignition switch
ON.
5 31S-LG11 (BK/WH) LH front turn lamp control ground
circuit
Less than 5 ohms between the FEM and the LH front turn lamp. Greater than 10 volts with the ignition switch
ON.
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Multifunction Switch C202
Instrument Cluster C220b
LH Front Parking/Turn Lamp C1023, RH Front Parking/Turn Lamp C1043
Pinpoint Test P: The Turn Signal Lamps Are Inoperative
Normal Operation
The instrument cluster sends out a voltage reference signal through circuit 8-LG43 (WH/VT) to the multifunction switch. The return signal is carried through circuit 9-LG43 (BN/WH) (shared
with the high beam circuit) back to the instrument cluster. When the multifunction switch is placed in the RH or LH turn positions, the voltage signal sent by the instrument cluster passes
through a resistor within the multifunction switch (specific to LH and RH turn positions) before returning to instrument cluster.
Possible Causes
circuit 8-LG43 (WH/VT) open, short to ground or short to power
multifunction switch
instrument cluster
PINPOINT TEST P: THE TURN SIGNAL LAMPS ARE INOPERATIVE
Pin Number
(s) Circuit Designation/Description Normal Condition/Measurement
7 8-LG43 (WH/VT) multifunction switch signal
output circuit
Less than 5 ohms between the multifunction switch and the instrument cluster. Greater than 10,000 ohms between the
instrument cluster and ground.
Pin Number
(s) Circuit Designation/Description Normal Condition/Measurement
20 8-LG43 (WH/VT) multifunction switch signal
output circuit
0 voltage, less than 5 ohms between the instrument cluster and the multifunction switch. Greater than 10,000 ohms
between the instrument cluster and ground.
Pin Number(s) Circuit Designation/Description Normal Condition/Measurement
1 (1023) 29S-LF7 (OG/BU) switched B+ circuit Greater than 10 volts with the ignition switch ON.
1 (1043) 29S-LF16 (OG/GN) switched B+ circuit Greater than 10 volts with the ignition switch ON.
Test Step Result / Action to Take
P1 CHECK THE HIGH BEAM OPERATION
Ignition ON.
Turn the headlamp switch to the headlamps ON position.
Place the multifunction switch in the high beam position.
Do the high beams operate correctly?
Yes
TURN the headlamp switch OFF. GO to P2.
No
GO to Pinpoint Test B to diagnose the high
beams.
P2 CHECK THE MULTIFUNCTION SWITCH OUTPUT
Ignition OFF.
Connect the scan tool.
Ignition ON.
Monitor the instrument cluster turn signal status PID while placing the multifunction switch in the RH and then LH turn
positions.
Does the PID match with the multifunction switch positions?
Yes
GO to P6.
No
GO to P3.
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Pinpoint Test Q: One Turn Signal Lamp Is Inoperative
Normal Operation
Power is supplied from the central junction box (CJB) to the LH front turn signal lamp through circuits 29S-LF3 (OG/YE) and 29S-LF7 (OG/BU). The ground for the LH front turn signal lamp
is passed through circuit 31S-LG11 (BK/WH) to the front electronic module (FEM). Power is supplied from the CJB to the RH front turn signal lamp through circuits 29S-LF4 (OG/BU) and
29S-LF16 (OG/GN). The ground for the RH front turn signal lamp is passed through circuit 31S-LG18 (BK/YE) to the FEM. The FEM and rear electronic module (REM) individually control
the ground circuits for the turn signal lamps. The timed on/off cycle is determined in the instrument cluster programming and is set to flash approximately 80 times per minute if both the
front and rear turn signal lamps are good. If any turn signal lamp is not good, the instrument cluster will flash the remaining working turn signal lamp(s) approximately 160 times per minute.
Possible Causes
circuit 29S-LF7 (OG/BU) open
circuit 29S-LF16 (OG/GN) open
circuit 31S-LG11 (BK/WH) open or short to power
circuit 31S-LG18 (BK/YE) open or short to power
FEM
REM
PINPOINT TEST Q: ONE TURN SIGNAL LAMP IS INOPERATIVE
P3 CHECK THE MULTIFUNCTION SWITCH
Ignition OFF.
Disconnect: Multifunction Switch C202.
Carry out the multifunction switch component test.
Refer to Wiring Diagrams Cell 149 for component testing.
Is the multifunction switch OK?
Yes
GO to P4.
No
INSTALL a new multifunction switch. REFER to
Section 211-00. TEST the system for normal
operation.
P4 CHECK CIRCUIT 8-LG43 (WH/VT) FOR AN OPEN OR SHORT TO GROUND
Disconnect: Instrument Cluster C220b.
Measure the resistance between the instrument cluster C220b-20, circuit 8-LG43 (WH/VT), harness side and the
multifunction switch C202-7, circuit 8-LG43 (WH/VT), harness side; and between the instrument cluster C220b-20, circuit
8-LG43 (WH/VT), harness side and ground.
Is the resistance less than 5 ohms between the instrument cluster and the multifunction switch; and greater than
10,000 ohms between the instrument cluster and ground?
Yes
GO to P5.
No
REPAIR the circuit. TEST the system for normal
operation.
P5 CHECK CIRCUIT 8-LG43 (WH/VT) FOR SHORT TO POWER
Ignition ON.
Measure the voltage between the instrument cluster C220b-20, circuit 8-LG43 (WH/VT), harness side and ground.
Is any voltage present?
Yes
REPAIR the circuit. TEST the system for normal
operation.
No
GO to P6.
P6 CHECK FOR INSTRUMENT CLUSTER OPERATION
Ignition OFF.
Disconnect all instrument cluster connectors.
Check for:
corrosion
pushed-out pins
Connect all instrument cluster connectors and make sure they seat correctly.
Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new instrument cluster. REFER to
Section 413-00. TEST the system for normal
operation.
No
The system is operating correctly at this time.
Concern may have been caused by a loose or
corroded connector. REPEAT the self-test.
Test Step Result / Action to Take
Q1 CHECK THE STOPLAMPS
Press the brake pedal and observe the stoplamps.
Do the stoplamps operate correctly?
Yes
If a front turn signal is inoperative, GO to Q2.
If a rear turn signal is inoperative, GO to Q5.
No
REFER to Stoplamps in this section to continue diagnostics.
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Pinpoint Test R: One Turn Signal Lamp Is Always On
Normal Operation
Power is supplied from the central junction box (CJB) to the LH front turn signal lamp through circuits 29S-LF3 (OG/YE) and 29S-LF7 (OG/BU). The ground for the LH front turn signal lamp
is passed through circuit 31S-LG11 (BK/WH) to the front electronic module (FEM). Power is supplied from the CJB to the RH front turn signal lamp through circuits 29S-LF4 (OG/BU) and
29S-LF16 (OG/GN). The ground for the RH front turn signal lamp is passed through circuit 31S-LG18 (BK/YE) to the FEM. The FEM individually controls the ground circuits for the front turn
signal lamps. The timed on/off cycle is determined in the instrument cluster programming and is set to flash approximately 80 times per minute if both the front and rear turn signal lamps
are good. If any turn signal lamp is not good, the instrument cluster will flash the remaining working turn signal lamp(s) approximately 160 times per minute.
Possible Causes
circuit 31S-LG11 (BK/WH) short to ground
circuit 31S-LG18 (BK/YE) short to ground
FEM
Q2 CHECK THE POWER SUPPLY TO THE TURN SIGNAL LAMP
Ignition OFF.
Disconnect: Inoperative Turn Signal Lamp.
Ignition ON.
Measure the voltage between the inoperative lamp and ground as follows:
Is the voltage greater than 10 volts?
Inoperative Turn Signal Lamp Connector-Pin Circuit
LH front parking/turn signal lamp C1023-1 29S-LF7 (OG/BU)
RH front parking/turn signal lamp C1043-1 29S-LF16 (OG/GN)
Yes
GO to Q3.
No
REPAIR the circuit in question. CLEAR the DTCs. TEST the system for normal operation.
Q3 CHECK THE CONTROL GROUND CIRCUIT FOR AN OPEN OR SHORT
TO POWER
Ignition OFF.
Connect: Inoperative Turn Signal Lamp.
Disconnect: FEM C201a.
Ignition ON.
NOTE: If the fuse in the jumper wire fails, repair the circuit for short to
power.
Connect a fused (5A) jumper wire between the FEM and ground as
follows:
Does the inoperative lamp now illuminate?
Inoperative Turn Signal Lamp FEM Connector Circuit
LH front parking/turn signal lamp FEM C201a-5 31S-LG11 (BK/WH)
RH front parking/turn signal lamp FEM C201a-4 31S-LG18 (BK/YE)
Yes
GO to Q4.
No
REPAIR the circuit in question. CLEAR the DTCs. TEST the system for normal operation.
Q4 CHECK FOR FEM OPERATION
Ignition OFF.
Disconnect all FEM connectors.
Check for:
corrosion
pushed-out pins
Connect all FEM connectors and make sure they seat correctly.
Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new FEM. REFER to Section 418-00. TEST the system for normal operation.
No
The system is operating correctly at this time. Concern may have been caused by a loose or
corroded connector. REPEAT the self-test.
Q5 CHECK FOR REM OPERATION
Ignition OFF.
Disconnect all REM connectors.
Check for:
corrosion
pushed-out pins
Connect all REM connectors and make sure they seat correctly.
Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new REM. REFER to Section 418-00. TEST the system for normal operation.
No
The system is operating correctly at this time. Concern may have been caused by a loose or
corroded connector. REPEAT the self-test.
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PINPOINT TEST R: ONE TURN SIGNAL LAMP IS ALWAYS ON
Pinpoint Test S: The Hazard Lamps Are Always On
Normal Operation
The instrument cluster sends out a voltage reference signal through circuit 8-LG43 (WH/VT) to the multifunction switch. The return signal is carried through circuit 9-LG43 (BN/WH) (shared
with the high beam circuit) back to the instrument cluster. When the hazard switch is engaged, the voltage signal sent by the instrument cluster passes directly through the multifunction
switch and returns to the instrument cluster.
Possible Causes
circuit 8-LG43 (WH/VT) short to ground
multifunction switch
instrument cluster
PINPOINT TEST S: THE HAZARD LAMPS ARE ALWAYS ON
Test Step Result / Action to Take
R1 DETERMINE THE ALWAYS ON LAMP
Ignition ON.
Observe the turn signal lamps.
Is a rear lamp illuminated?
Yes
REFER to Stoplamps in this section to diagnose the stoplamps.
No
GO to R2.
R2 CHECK CIRCUIT 31S-LG11 (BK/WH) (LH TURN LAMP) OR 31S-
LG18 (BK/YE) (RH
TURN LAMP) FOR SHORT TO GROUND
Ignition OFF.
Disconnect: FEM C201a.
Ignition ON.
Observe the turn signal lamp after disconnecting the FEM.
Does the lamp continue to illuminate?
Yes
REPAIR the circuit in question. CLEAR the DTCs. TEST the system for normal
operation.
No
GO to R3.
R3 CHECK FOR FEM OPERATION
Ignition OFF.
Disconnect all FEM connectors.
Check for:
corrosion
pushed-out pins
Connect all FEM connectors and make sure they seat correctly.
Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new FEM. REFER to Section 418-00. TEST the system for normal
operation.
No
The system is operating correctly at this time. Concern may have been caused by a
loose or corroded connector. REPEAT the self-test.
Test Step Result / Action to Take
S1 CHECK THE MULTIFUNCTION SWITCH
Ignition OFF.
Disconnect: Multifunction Switch C202.
Carry out the multifunction switch component test.
Refer to Wiring Diagrams Cell 149 for component testing.
Is the multifunction switch OK?
Yes
GO to S2.
No
INSTALL a new multifunction switch. REFER to Section 211-00. CLEAR the
DTCs. TEST the system for normal operation.
S2 CHECK CIRCUIT 8-LG43 (WH/VT) FOR SHORT TO GROUND
Disconnect: Instrument Cluster C220b.
Measure the resistance between the multifunction switch C202-7, circuit 8-LG43
(WH/VT), harness side and ground.
Is the resistance less than 5 ohms?
Yes
REPAIR the circuit. CLEAR the DTCs. TEST the system for normal operation.
No
GO to S3.
S3 CHECK FOR INSTRUMENT CLUSTER OPERATION
Ignition OFF.
Disconnect all instrument cluster connectors.
Check for:
corrosion
pushed-out pins
Connect all instrument cluster connectors and make sure they seat correctly.
Operate the system and verify the concern is still present.
Is the concern still present?
Yes
INSTALL a new instrument cluster. REFER to Section 413-00. TEST the system
for normal operation.
No
The system is operating correctly at this time. Concern may have been caused by
a loose or corroded connector. REPEAT the self-test.
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